Angle attachment for power tool

ABSTRACT

An angle attachment of a hand-held power tool, such as a spiral cutting tool, includes an angle attachment housing having an open first end adapted to be attached to the motor housing of the power tool. An alignment bearing is mounted in the angle attachment housing and adapted to receive and support a first shaft having a first shaft gear mounted thereon. An attachment shaft is mounted in the angle attachment housing at an angle, e.g., a right angle, to the first shaft. The attachment shaft includes an attachment shaft gear mounted thereon which is engaged with the first shaft gear. One or more attachment shaft bearings are mounted in the angle attachment housing to support the attachment shaft for rotational movement thereof. The first shaft is coupled to a motor shaft of the power tool before the angle attachment housing is attached to the power tool motor housing. Rotation of the first shaft by the power tool motor causes rotation of attachments attached to the attachment shaft mounted at an angle to the first shaft by means of the gear mechanism formed by the engaged first shaft gear and attachment shaft gear.

FIELD OF THE INVENTION

This invention pertains generally to hand-held power tools such asspiral cutting tools, and more particularly to cutting, sanding, andother accessories and/or attachments for such power tools.

BACKGROUND OF THE INVENTION

A spiral cutting tool is a hand-held power tool having an electric motorthat rotates a spiral cutting tool bit at very high speeds. A typicalspiral cutting tool includes an electric motor enclosed within agenerally cylindrical motor housing. The motor drives a motor shaftwhich extends from one end of the motor housing along the axis thereof.A mechanical structure, such as a conventional drill-type chuck or acollet-type system, is mounted on the end of the motor shaft outside ofthe motor housing, for attaching, e.g., a spiral cutting tool bit to themotor shaft. The spiral cutting tool bit is designed for cuttingperpendicular to the axis of the bit. A spiral cutting tool is thus usedto remove material from a work piece by moving the rotating spiralcutting tool bit through the work piece in a direction perpendicular tothe axis of rotation of the bit. Thus, a spiral cutting tool isconventionally operated by grasping the motor housing with one or bothhands, and/or grasping a handle attached to the motor housing, turningon the electric motor to begin high speed rotation of the spiral cuttingtool bit, plunging the spinning cutting tool bit into a work piece, suchas a piece of wood, and then moving the cutting bit through the workpiece in a direction perpendicular to the axis of the spiral cuttingtool bit by moving the motor housing in a direction parallel to theplane of the work piece surface while keeping the axis of the motorhousing generally perpendicular to the work piece surface.

The utility of a spiral cutting tool may be enhanced by attachingaccessories other than spiral cutting tool bits to the motor shaftextending from the spiral cutting tool housing, to be rotated by thehigh-speed spiral cutting tool motor within the housing. For example, acutting wheel or sanding disk might be attached to the spiral cuttingtool motor shaft to be driven by the high-speed spiral cutting toolmotor. The use of such attachments might expand the utility of thespiral cutting tool to various other cutting and sanding operations.However, the utility of a spiral cutting tool for such operations islimited if the cutting wheel or sanding disk is attached directly to theend of the motor shaft extending from the end of the motor housing. Insuch a case, the orientation of the cutting wheel or sanding disk withrespect to the motor housing prevents effective use of the spiralcutting tool for cutting wheel and sanding operations, due to limitedcontrol and visibility.

What is desired, therefore, is an attachment for a spiral cutting tool,or other hand-held power tool, which allows cutting wheels, sandingdisks, and similar attachments to be coupled to the spiral cutting toolmotor, to be driven thereby, in a useful orientation with respect to thecutting tool motor housing. Such an attachment is preferably removablyattachable to the spiral cutting tool, so that the spiral cutting toolor other hand-held power tool may be converted easily for use in wheelcutting or sanding operations, and re-converted back for use with, e.g.,spiral cutting tool bits, etc.

SUMMARY OF THE INVENTION

The present invention provides an angle attachment for spiral cuttingtools and other similar hand-held power tools. An angle attachment inaccordance with the present invention may be removably coupled to themotor shaft of a spiral cutting tool or other hand-held power tool, andtransfers the rotational motion of the motor shaft of the tool to anattachment shaft mounted at an angle, for example, at a right angle, tothe motor shaft. Attachments, such as a cutting wheel or a back-up padhaving a sanding disk mounted thereon, may be attached to the attachmentshaft, and rotated thereby at a high speed by the spiral cutting toolmotor via the angle attachment. An angle attachment in accordance withthe present invention thus enhances the utility of a spiral cutting toolor similar hand-held power tool by allowing such a tool to be used todrive cutting wheels, sanding disks, and similar attachments in a usefulorientation with respect to the spiral cutting tool housing such thatvisibility and control are not compromised.

An angle attachment in accordance with the present invention includes anangle attachment housing, in which the other components of the angleattachment are positioned and mounted. The angle attachment housing maybe made of a sturdy rigid material, such as hard plastic or metal. Theangle attachment housing preferably includes a structure for attachingthe angle attachment housing to the motor housing of a spiral cuttingtool or other similar hand-held power tool. Such a structure mayinclude, for example, one or more slots formed adjacent to an open firstend of the angle attachment housing, which allow the open first end ofthe angle attachment housing to expand slightly. This allows the openfirst end of the angle attachment housing to be positioned over andaround an end of a spiral cutting motor tool housing, around thelocation where a motor shaft emerges from the housing. One or morescrews, bolts, or other fasteners are preferably mounted on the firstend of the angle attachment housing, and extend across the slots formedtherein. After positioning the first end of the angle attachment housingon the cutting tool motor housing, the fasteners are tightened, therebydrawing portions of the angle attachment housing on either side of theslots together, to secure the first end of the angle attachment housingto the cutting tool motor housing.

A gear mechanism is positioned in the angle attachment housing fortransferring the rotational motion of the cutting tool motor shaftdriven by the cutting tool motor to an attachment shaft mounted at anangle, e.g., a right angle, thereto. A first shaft positioned in theangle attachment housing is removably attachable to an end of thecutting tool motor shaft extending from the cutting tool housing, via amechanical structure, such as a collet-type system, mounted on the endof the motor shaft. A first shaft gear is mounted on the first shaft,such that when the first shaft is rotated by the cutting tool motorshaft, the first shaft gear is also rotated. The first shaft issupported in the angle attachment housing by an alignment bearingassembly mounted therein. For example, a distal end of the first shaftis preferably inserted into a central aperture of the alignment bearingassembly mounted in the angle attachment housing.

An attachment shaft is mounted in the angle attachment housing at anangle, such as a right angle, to the first shaft which is attached tothe cutting tool motor shaft. An attachment shaft gear is mounted on theattachment shaft. The attachment shaft gear is positioned on theattachment shaft such that the attachment shaft gear engages the firstshaft gear mounted on the first shaft when the first shaft is positionedin the angle attachment housing to be supported by the alignmentbearing. Thus, rotation of the first shaft attached to the cutting toolmotor shaft causes rotation of the attachment shaft, mounted at an anglethereto, via the gear mechanism formed by the first shaft gear mountedon the first shaft and the attachment shaft gear mounted on theattachment shaft. The attachment shaft is supported for rotationalmovement in the angle attachment housing via one or more attachmentshaft bearing assemblies mounted therein. Preferably at least twoattachment shaft bearing assemblies are employed. Two attachment shaftbearing assemblies mounted in the angle attachment housing to supportthe attachment shaft on either side of the attachment shaft gear arepreferred.

To attach an angle attachment in accordance with the present inventionto a spiral cutting tool, or other hand-held power tool, the first shaftis attached to the end of the tool motor shaft by the collet-type systemor other mounting structure provided thereon. The first shaft is thenpositioned in the motor housing. Hand-held power tools, and especiallyspiral cutting tools, employ very high-speed motors. For example, aspiral cutting tool may employ an AC electric motor with a no-loadrotation speed of 30,000 RPM. Thus, the first shaft and attachment shaftof an angle attachment in accordance with the present invention may bedriven at very high speeds. Particularly at such high speeds, it iscritical that the relative positions of the first shaft and theattachment shaft be established properly and maintained to preventslipping of the gear mechanism formed by the first shaft gear and theattachment shaft gear. The use of an alignment bearing assembly mountedin a fixed position in the angle attachment housing ensures that thefirst shaft is properly positioned and oriented in the angle attachmenthousing with respect to the attachment shaft, such that the gearmechanism formed by the gears mounted on the first shaft and theattachment shaft is properly established and maintained. Thus, eventhough the first shaft is removable from and insertable into theattachment housing by a user, the alignment bearing is mounted in theattachment housing in a fixed position in relation to the attachmentshaft mounted in the attachment housing, and the attachment shaft gearmounted thereto. Thus, proper engagement of the first shaft gear and theattachment shaft gear is established and maintained when the first shaftis positioned in the angle attachment housing by, for example, insertingthe distal end of the first shaft into the central aperture of thealignment bearing assembly.

Various attachments may be attached to the attachment shaft by, forexample, an attachment mounting structure formed at an end of theattachment shaft extending from a second end of the angle attachmenthousing. For example, an attachment flange may be mounted on the end ofthe attachment shaft extending from the angle attachment housing, with aportion of the attachment shaft extending distally beyond the attachmentflange being threaded. An attachment to be driven by the attachmentshaft, such as, for example, a cutting wheel, may be mounted on theattachment shaft by, for example, placing the cutting wheel against theattachment flange, with the threaded portion of the attachment shaftextending through a central aperture formed in the cutting wheel,threading a flange nut over the threaded portion of the attachmentshaft, and tightening the flange nut down against the cutting wheel topress the cutting wheel tightly against the attachment flange, tothereby attach the cutting wheel securely to the attachment shaft.Alternatively, an attachment, such as a back-up pad, upon which sandingdisks may be mounted, may be mounted on the end of the attachment shaftby simply threading the attachment onto the threaded end of theattachment shaft until the attachment rests tightly against theattachment shaft flange.

An angle attachment in accordance with the present invention may beattached to a spiral cutting tool or other hand-held power tool in thefollowing manner. The first shaft is first attached to an end of thecutting tool motor shaft extending from the cutting tool housing, e.g.,via a collet-type system. The open first end of the attachment housingis then positioned around the end of the cutting tool housing, aroundthe location where the motor shaft emerges from the housing, by slidingthe open first end of the attachment housing around the end of thecutting tool housing. In so doing, a distal end of the first shaftattached to the cutting tool motor shaft is extended into the centralaperture of the first shaft alignment bearing mounted in the angleattachment housing, thereby positioning the first shaft in the angleattachment housing such that the first shaft gear mounted on the firstshaft is engaged with the attachment shaft gear mounted on theattachment shaft. The fasteners mounted on the attachment housing maythen be tightened to secure the angle attachment housing and, therefore,the entire angle attachment, securely on the cutting tool motor housing.An attachment, such as a cutting wheel or back-up pad having sandingdisks mounted thereon, may then be mounted on the end of the attachmentshaft extending from the angle attachment housing, by, for example,threading the attachment thereon in the manner described previously. Thetool may then be operated for, e.g., cutting material, using the cuttingwheel, or sanding material, using a sanding disk mounted on the back-uppad, by grasping the cutting tool firmly, and turning on the cuttingtool motor. The rotating cutting tool motor will drive the cutting wheelor sanding disk at a high speed via the motor shaft, the first angleattachment shaft attached thereto, and the attachment shaft, mounted atan angle to the first shaft and coupled thereto via the gear mechanism.The angle with which the attachment shaft is positioned with respect tothe first shaft ensures that the attachment is positioned for use in anorientation providing good visibility and control.

Further objects, features, and advantages of the invention will beapparent from the following detailed description, taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a spiral cutting tool having an angleattachment in accordance with the present invention attached thereto.

FIG. 2 is a perspective view of an exemplary angle attachment inaccordance with the present invention having a cutting wheel attachmentmounted thereon.

FIG. 3 is a back view of the exemplary angle attachment of FIG. 2.

FIG. 4 is a front view of the exemplary angle attachment of FIG. 2.

FIG. 5 is a cross-sectional view of the exemplary angle attachment ofFIGS. 2-4, as taken along the line 5—5 of FIG. 4.

FIG. 6 is a perspective view of an exemplary angle attachment inaccordance with the present invention having a back-up pad attachmentfor supporting sanding disks mounted thereon.

FIG. 7 is a front view of the exemplary angle attachment of FIG. 6.

FIG. 8 is a cross-sectional view of the exemplary angle attachment ofFIGS. 6 and 7, as taken along the line 8—8 of FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

A spiral cutting tool 10 having an exemplary angle attachment 12 inaccordance with the present invention attached thereto is illustrated inFIG. 1. Although an exemplary angle attachment 12 in accordance with thepresent invention will be described in detail herein with reference touse thereof in combination with a spiral cutting tool 10, it should beunderstood that an angle attachment in accordance with the presentinvention may be employed in combination with other similar hand-heldpower tools as well.

The spiral cutting tool 10 includes a motor housing 14 to which theangle attachment 12 and a handle 16 are attached. The motor housing 14is preferably made of an electrically insulating material, such as hardplastic. The motor housing 14 is generally cylindrical in shape, andincludes raised gripping surfaces 15 formed thereon that allow a firmgrip on the cutting tool 10 to be maintained when the cutting tool 10 isgrasped around the motor housing 14.

The handle 16 is preferably made of an electrically insulating material,such as hard plastic. The handle 16 includes a gripping surface 18 whichis preferably contoured in shape so that the handle 16 may be graspedcomfortably in the hand of an operator of the cutting tool 10. Thehandle gripping surface 18 is preferably aligned substantially parallelwith the axis of the cutting tool housing 14. The handle 16 allows thecutting tool 10 to be grasped firmly and comfortably with two hands, toprovide greater control of the cutting tool 10 during operation, andthereby to provide for more accurate cuts with less operator fatigue.The handle 16 also allows the cutting tool 10 to be grasped more firmlyduring motor start-up, during which the reaction torque of the cuttingtool motor may cause the tool 10 to twist. Thus, the cutting tool handle16 also facilitates safe use of the cutting tool 10. It may bedesirable, however, that the cutting tool handle 16 be detached for someapplications. For example, for use of the tool 10 in close quarters orobstructed areas, the handle 16 may become an obstruction, and actuallyinterfere with accurate use of the tool 10. Thus, the handle 16 ispreferably made detachable from the cutting tool 10 when its use wouldinterfere with accurate and safe operation of the cutting tool 10. Forexample, the handle 16 may be securely but detachably attached to thecutting tool 10 using threaded locking knobs 20 which are insertedthrough mounting holes in ends of the handle 16 into correspondingthreaded holes formed in lugs (not shown) extending from the cuttingtool motor housing 14. To detach the handle 16 from the housing 14, thelocking knobs 20 are loosened and removed from the handle 16, and thehandle 16 is pulled away from the housing 14.

One or more storage compartments 22 and 24 may be formed in thedetachable handle 16. One of the handle storage compartments 22 maypreferably be specifically designed to hold a wrench 26 for use intightening and loosening a mechanical structure for attachingattachments to the spiral cutting tool 10, as will be described in moredetail below. Other compartments 24 may preferably be covered by acompartment door, such as a sliding door 28, to prevent objects storedin the compartment 24 from sliding out during use of the tool 10. Anexemplary and preferred detachable handle 16 which may be used incombination with the spiral cutting tool 10 is described in U.S. Pat.No. 5,813,805, the disclosure of which is incorporated herein byreference.

An electric motor (not visible in FIG. 1) is enclosed within the motorhousing 14. An exemplary electric motor that may be employed is aconventional 4 amp 115-120 V, AC electric motor with a no-load rotationspeed of 30,000 rpm. The motor may receive electrical power through anelectrical power cord connected to an AC power source, or from adetachable battery pack mounted on the cutting tool 10 (not shown inFIG. 1). An exemplary and preferred detachable battery pack which may beused in combination with the spiral cutting tool 10 is described in U.S.Pat. No. 5,902,080, the disclosure of which is incorporated herein byreference. The electric motor is turned on and off by an on/off switchon the motor housing 14 (not shown in FIG. 1).

The electric motor of the cutting tool 10 drives a motor shaft. A fan,located within the motor housing 14, is preferably attached to the motorshaft. When the motor is turned on, by means of the on/off switch, thefan is rotated at a high speed to draw air through the motor housing 14,and across the electric motor, thereby to cool the motor. For thispurpose, air intake and exhaust vents 30 are preferably provided in themotor housing 14. Cool air is thus drawn by the motor fan into the motorhousing 14 through the air intake vents to cool the electric motor, withwarm air exhausted from the motor housing 14 through the exhaust airvents.

An end of the motor shaft extends from one end of the motor housing 14.Mounted on the end of the motor shaft is a mechanical structure 32 (seeFIGS. 3, 5, and 8) for attaching attachments to the motor shaft.Although a conventional drill-type chuck may be used for the structure32 for mechanically attaching attachments to the motor shaft, thepreferred structure 32 for securing attachments to the motor shaft is acollet-type system. A collet attachment system includes a collet nut andcollet centered axially within a central aperture of the collet nut. Thecollet nut is mounted on a threaded end of the motor shaft. To secure anattachment to the motor shaft, a shank or shaft of the attachment isinserted into the central aperture of the collet. The collet nut is thentightened, first by hand and then with a wrench, e.g., the wrench 26,until the attachment shaft or shank is housed securely. As the colletnut is tightened down on the threaded end of the motor shaft, the colletis compressed within the collet nut between a partially enclosed end ofthe collet nut and the motor shaft. The collet is slotted and hastapered ends such that when the collet is compressed between the colletnut and the motor shaft, the collet is compressed radially, causing thecentral aperture of the collet to close tightly around the shank orshaft of the attachment to be attached to the motor shaft. To remove theattachment from the motor shaft, the collet nut is loosened, e.g., usingthe wrench 26, until the attachment shaft can be easily removed from thecentral aperture of the collet.

A shaft lock pin 34 is preferably provided to prevent rotation of themotor shaft when the collet nut is being loosened and tightened. Theshaft lock pin 34 extends through the motor housing 14. When the shaftlock pin 34 is depressed, it engages the motor shaft, preventingrotation of the shaft, and allowing the collet nut to be loosened andtightened. When the shaft lock pin 34 is released, a spring (not shown)attached to the shaft lock pin 34 causes the shaft lock pin 34 to becomedisengaged from the motor shaft, allowing free rotation thereof.

An angle attachment 12 in accordance with the present invention will nowbe described in further detail with reference to FIGS. 2-5. The angleattachment 12 includes an angle attachment housing 36, which containsand encloses the other components of the angle attachment 12, and bywhich the angle attachment 12 is attached to the housing 14 of thecutting tool 10. The angle attachment housing 36 is preferably made ofan electrically insulating material, such as hard plastic. The housing36 may be formed of such a material in two complementary and symmetrichalves by a conventional molding process. The two halves are then joinedtogether to form the complete housing 36. The two halves of theattachment housing 36 may be joined together in a conventional manner,for example, using an adhesive. The two halves of the attachment housing36 are preferably also joined together using fasteners, such as screws38. For this purpose, complimentary fastener holes 40 may be provided inthe halves of the angle attachment housing 36.

The angle attachment housing 36 includes an open first end 42, which isadapted to receive an end of the cutting tool housing 14 located aroundthe location where the motor shaft emerges from the housing 14, therebyto attach the angle attachment housing 36 to the cutting tool motorhousing 14. One or more slots 44, or similar structures, may be formedextending inwardly from the open first end 42 of the angle attachmenthousing 36. For example, slots 44 preferably may be formed at twolocations around the open first end 42 of the angle attachment housing36, e.g., opposite each other across the open end 42. The slots 44,formed in the rigid or semi-rigid material of which the angle attachmenthousing 36 is made, permit the open first end 42 of the angle attachmenthousing 36 to expand slightly, thereby allowing the open first end 42 ofthe angle attachment housing 36 to be slid over the end of the cuttingtool housing 14.

Spring force created by portions of the angle attachment housing 36 oneach side of the slots 44 holds the open first end 42 of the angleattachment housing 36 on the cutting tool motor housing 14 when attachedthereto. This spring force, however, is typically not sufficient to holdthe angle attachment 12 in position on the cutting tool 10 during use.Therefore, a further mechanism preferably is provided for securing theopen first end 42 of the angle attachment housing 36 to the cutting toolhousing 14. For example, fasteners 46 may be provided to tighten theopen first end 42 of the angle attachment housing 36 around the end ofthe cutting tool motor housing 14. The fasteners 46, which may beimplemented as screws, bolts, or similar fasteners, preferably includinghand or screwdriver accessible fastener ends, may, for example, bemounted in extending portions 48 of the angle attachment housing 36positioned such that the fasteners 46 bridge the expansion slots 44formed adjacent to the open first end 42 of the angle attachment housing36. The extending portions 48 may be integrally formed on the angleattachment housing 36, and may preferably include threaded fastenerholes formed therein, into which the fasteners 46 are threaded. As thefasteners 46 are tightened, by hand, or with a screwdriver, wrench, orother tool, the fasteners 46 draw the extending portions 48 of the angleattachment housing 36 together, thereby partially closing the slots 44formed therein, to reduce the circumference of the open first end 42 ofthe angle attachment housing 36, thereby tightening the open end 42 ofthe angle attachment housing 36 around the end of the cutting tool motorhousing 14, to attach the angle attachment housing 36 securely thereto.

Within the angle attachment housing 36 there is positioned a first shaft50, upon which a first shaft gear 52 is mounted, and an attachment shaft54, upon which an attachment shaft gear 56 is mounted. (See, e.g., FIG.5.) The first shaft gear 52 and attachment shaft gear 56 may be fixedlyattached to the first shaft 50 and attachment shaft 54, respectively, ina conventional manner. The first shaft 50, first shaft gear 52,attachment shaft 54, and attachment shaft gear 56, may be made in aconventional manner of strong wear resistant materials, e.g., steel.

The first shaft 50 and attachment shaft 54 are positioned in the angleattachment housing 36 such that a proximal end 58 of the first shaft 50extends toward the open first end 42 of the angle attachment housing 36along an axis thereof, such that the attachment shaft 54 is mounted atan angle, e.g., a right angle, to the first shaft 50 and an attachmentend 60 thereof extends from a second end of the angle attachment housing36, and such that the first shaft gear 52 mounted on the first shaft 50is engaged with the attachment shaft gear 56 mounted on the attachmentshaft 54. In this manner, rotation of the first shaft 50 is translatedto rotation of the attachment shaft 54, mounted at an angle thereto, viathe gears 52 and 56, thereby to rotate an attachment, such as a cuttingwheel or back-up pad for a sanding disk, attached to the attachment end60 of the attachment shaft 54, in a manner to be described in moredetail below.

The attachment shaft 54 is preferably mounted for rotational movement ina fixed axial position in the angle attachment housing 36. At least onebearing assembly 62 or 64 is preferably fixedly mounted in the angleattachment housing 36 around the attachment shaft 54 to providerotational bearing support for the attachment shaft 54. Preferably twobearing assemblies 62 and 64 are employed, with each bearing assembly 62and 64 mounted in the angle attachment housing 36 in a conventionalmanner and one bearing assembly 62 or 64 positioned along the attachmentshaft 54 on each side of the attachment shaft gear 56, i.e., on eachside of the position where the first shaft gear 52 engages theattachment shaft gear 56. The bearing assemblies 62 and 64 may beimplemented in a conventional manner, e.g., as ball bearing assemblies.

The first shaft 50, having the first gear 52 mounted thereon, ispreferably removably mounted in the angle attachment housing 36. Thisallows the first shaft 50 to be attached to the end of the cutting toolmotor shaft, by means of the mechanical structure 32 mounted thereon forthis purpose, before the angle attachment 12 is attached to the cuttingtool 10. To ensure proper operation of an angle attachment 12 inaccordance with the present invention, the first shaft 50, attached tothe motor shaft, must be positioned and remain in proper alignment withthe attachment shaft 54, such that the gears 52 and 56 mounted on thefirst shaft 50 and the attachment shaft 54, respectively, remain engagedduring operation. This is particularly important where the angleattachment 12 is used as an attachment for a spiral cutting tool, havinga very high motor rotation speed.

In accordance with the present invention, proper alignment between thefirst shaft 50 and the attachment shaft 54 is established and maintainedby an alignment bearing 66. The alignment bearing 66 may be implementedin a conventional manner, e.g., as a ball bearing assembly, and ismounted in a fixed position in the angle attachment housing 36 in aconventional manner. The alignment bearing assembly 66 is positioned inthe angle attachment housing 36 such that, when the first shaft 50 issupported thereby for rotational movement thereof, the attachment shaft54 is positioned at the desired angle with respect to the first shaft50, and the gears 52 and 56 remain engaged.

The first shaft 50 preferably includes a distal end 68 which extendsbeyond the position of the first shaft gear 52 mounted on the firstshaft 50. The distal end 68 of the first shaft 50 may have a smallercircumference than the remainder of the first shaft 50. The distal end68 is sized and shaped to be inserted into, and supported by, thealignment bearing assembly 66. For example, the distal end 68 of thefirst shaft 50 may be sized and shaped to fit into a central aperture ofthe alignment bearing assembly 66.

An angle attachment 12 in accordance with the present invention may beemployed in combination with various attachments which are attached tothe end 60 of the attachment shaft 54 which extends from the angleattachment housing 36. An attachment mounting structure is preferablyformed at the end 60 of the attachment shaft 54 to provide a means forattaching various attachments thereto. For example, an attachment flange70 may be fixedly mounted on the end 60 of the attachment shaft 54,around the attachment shaft 54 where the attachment shaft 54 emergesfrom the angle attachment housing 36. A portion 72 of the end 60 of theattachment shaft 54 extends beyond the attachment flange 70. Thisportion 72 of the attachment shaft 54 is preferably at least partiallythreaded.

An attachment, such as, for example, a cutting wheel 74, may be attachedto the attachment shaft 54 by, for example, placing the cutting wheel 74against the mounting flange 70, with the threaded portion 72 of theattachment shaft 54 extending through a central aperture formed in thecutting wheel 74. A flange nut 76 may then be threaded over the threadedportion 72 of the attachment shaft 54, and tightened down against thecutting wheel 74, to press the cutting wheel 74 tightly against theattachment flange 70, thereby attaching the cutting wheel 74 securely tothe attachment shaft 54. The cutting wheel 74 may be removed from theattachment shaft 54 by loosening the flange nut 76, removing the flangenut 76 from the threaded end 72 of the attachment shaft 54, and thenremoving the cutting wheel 74 from the end 60 of the attachment shaft54.

An angle attachment 12 in accordance with the present invention may beemployed for sanding operations by attaching a sanding disk back-up pad78 to the end 60 of the attachment shaft 54, as illustrated, forexample, in FIGS. 6-8. The back-up pad 78 has a bottom surface 80, towhich sanding disks may be attached, in a conventional manner, e.g.,using an adhesive. The back-up pad 78 preferably includes a mountingstructure 82 positioned centrally thereon. The mounting structure 82preferably includes a threaded central aperture 84. The threaded centralaperture 84 of the back-up pad mounting structure 82 may be threadedonto the threaded end 72 of the attachment shaft 54. The back-up pad 78may be tightened against the attachment shaft flange 70, thereby toattach the back-up pad 78 to the end 60 of the attachment shaft 54. Theback-up pad mounting structure 82 preferably includes a hex nut 86 orsimilar configuration which facilitates tightening the back-up padattachment 78 onto the attachment shaft 54 using a wrench or othersimilar tool.

Means preferably are provided for temporarily preventing rotation of theattachment shaft 54 to facilitate the attachment of attachments thereto,and the removal of attachments therefrom. When the angle attachment 12is attached to the spiral cutting tool 10, rotation of the attachmentshaft 54 may be prevented, temporarily, when attachments are beingattached thereto or removed therefrom, by depressing the shaft lock pin34 on the spiral cutting tool 10. As described previously, when theshaft lock pin 34 is depressed, it engages the spiral cutting tool motorshaft, preventing rotation of the shaft. Since the spiral cutting toolmotor shaft is coupled to the attachment shaft 54, via the first shaft50, the first shaft gear 52, and the attachment shaft gear 56,depressing the shaft lock pin 34 when the angle attachment 12 isattached to the spiral cutting tool 10 also prevents rotation of theattachment shaft 54. When the shaft lock pin 34 is released, the shaftlock pin 34 becomes disengaged from the motor shaft, allowing freerotation thereof, as well as free rotation of the attachment shaft 54.

It may be desirable to attach attachments to the attachment shaft 54, orremove attachments therefrom, when the angle attachment 12 is notattached to the spiral cutting tool 10. To facilitate the attachment ofattachments to the attachment shaft 54, and the removal of attachmentstherefrom, when the angle attachment 12 is not attached to the spiralcutting tool 10, an attachment shaft lock mechanism 88 is preferablyprovided on the angle attachment 12. The attachment shaft lock 88 may beimplemented in a conventional manner to engage the attachment shaft 54when depressed or moved, thereby preventing rotation of the shaft 54,and allowing attachments to be attached to or removed from the end 60thereof. A spring release (not shown) is preferably provided to causethe attachment shaft lock mechanism 88 to become automaticallydisengaged from the attachment shaft 54, allowing free rotation thereof,when the attachment shaft lock mechanism 88 is not operated.

For safety purposes, a safety guard 90 is preferably provided on theangle attachment 12. The safety guard 90 may be implemented in aconventional manner, and is attached to the angle attachment 12 on thesecond end of the angle attachment housing 36, where the attachmentshaft 54 emerges from the angle attachment housing 36, and where variousattachments are attached thereto. The safety guard 90 is positioned onthe angle attachment housing 36 such that if an operator's hand graspingthe motor housing 14 of a spiral cutting tool 10 to which the angleattachment 12 is attached slips forward along the motor housing 14, thehand is prevented from contacting an attachment, such as a cutting wheel74, attached to the end 60 of the attachment shaft 54, by the safetyguard 90.

An angle attachment 12 is accordance with the present invention may beattached to a spiral cutting tool 10, or other hand-held power tool, andemployed for a cutting or sanding operation in the following manner.With the spiral cutting tool 10 turned off, and disconnected from apower source, the proximal end 58 of the first shaft 50 is inserted intothe structure 32, e.g., the collet-type system, mounted on the end ofthe motor shaft of the spiral cutting tool 10. The spiral cutting toolshaft lock button 34 is depressed, to temporarily prevent rotation ofthe motor shaft, and the attachment structure 32 is tightened, e.g.,using the wrench 26, to securely attach the first shaft 50 to the motorshaft. The shaft lock button 34 may then be released. The open first end42 of the angle attachment housing 36 is then positioned around the endof the cutting tool motor housing 14, around the location where themotor shaft emerges from the housing 14, by sliding the open first end42 of the angle attachment housing 36 around the end of the cutting toolhousing 14. In so doing, the distal end 68 of the first shaft 50 isextended into the central aperture of the alignment bearing 66 mountedin the angle attachment housing 36, thereby positioning the first shaft50 in the angle attachment housing 36 such that the first shaft gear 52engages the attachment shaft gear 56 mounted on the attachment shaft 54.The fasteners 46 mounted on the angle attachment housing 36 may then betightened to secure the angle attachment housing 36 and, therefore, theentire angle attachment 12, securely on the cutting tool motor housing14. An attachment, such as a cutting wheel 74 or back-up pad 78 havingsanding disks mounted thereon, may then be mounted on the end 60 of theattachment shaft 54 extending from the angle attachment housing 36 inthe manner described previously by, for example, threading theattachment thereon while depressing the shaft lock pin 34 temporarily toprevent rotation of the attachment shaft 54. The spiral cutting tool 10may then be operated for, e.g., cutting material, using the cuttingwheel 74, or sanding material, using a sanding disk mounted on theback-up pad 78, by grasping the cutting tool 10 firmly, and turning onthe cutting tool motor. The rotating cutting tool motor will drive thecutting wheel or sanding disk at a high speed via the motor shaft, thefirst shaft 50 attached thereto, and the attachment shaft 54, mounted atan angle to the first shaft 50, and coupled thereto via the first shaftgear 52 and the attachment shaft gear 56. The angle with which theattachment shaft 54 is positioned with respect to the first shaft 50ensures that the attachment is positioned for use in an orientationproviding good visibility and control.

The safety guard 90 may preferably include an adjustable foot 100attached thereto. The adjustable foot 100 includes a slot 102 formedtherein. A cutting wheel 74, when mounted on the angle attachment 12,extends through the slot 102. A leading edge 104 of the foot 100 may becurved backward slightly. The foot 100 may be attached to the safetyguard 90 by a screw 106 or other fastener which allows the position ofthe foot 100 to be adjusted. The foot 100 may thus be positioned suchthat the depth of a cut made by a cutting wheel 74 mounted on the angleattachment 12 may be adjusted when a cut is made by placing a face 108of the foot 100 along a workpiece being cut.

It should be understood that the present invention is not confined tothe particular exemplary embodiments or applications herein illustratedand described, but embraces such modified forms thereof as come withinthe scope of the following claims.

1. A removable angle attachment for a power tool, comprising: (a) anangle attachment housing; (b) an attachment shaft mounted provided inthe angle attachment housing and having an attachment end extendingtherefrom ; (c) a first an attachment shaft bearing mounted provided inthe angle attachment housing and positioned therein configured tosupport the attachment shaft for rotational movement thereof; (d) anattachment shaft gear attached to the attachment shaft; and (e) analignment bearing mounted positioned in the angle attachment housing andadapted to removably receive a distal end of a first shaft having afirst shaft gear mounted thereon to support the first shaft forrotational movement thereof and positioned in the angle attachmenthousing such that when the first shaft is positioned in the alignmentbearing the attachment shaft is at an angle to the first shaft and theattachment shaft gear is engaged with the first shaft gear.
 2. The angleattachment of claim 1 wherein the angle attachment housing includes anopen first end and wherein the alignment bearing is mounted in the angleattachment housing in alignment with an axis of the open first end ofthe angle attachment housing.
 3. An angle attachment for a power tool,comprising: (a) an angle attachment housing including an open first endand wherein the open first end of the angle attachment housing is sizedand shaped adapted to fit around a portion of a motor housing of a powertool and further including means for securing the open first end of theangle attachment housing to the motor housing of the power tool; (b) anattachment shaft mounted in the angle attachment housing and having anattachment end extending therefrom; (c) a first attachment shaft bearingmounted in the angle attachment housing and positioned therein tosupport the attachment shaft for rotational movement thereof; (d) anattachment shaft gear attached to the attachment shaft; and (e) analignment bearing mounted in the angle attachment housing in alignmentwith an axis of the open first end of the angle attachment housing andadapted to receive a first shaft having a first shaft gear mountedthereon to support the first shaft for rotational movement thereof andpositioned in the angle attachment housing such that when the firstshaft is positioned in the alignment bearing the attachment shaft is atan angle to the first shaft and the attachment shaft gear is engagedwith the first shaft gear.
 4. The angle attachment of claim 3 whereinthe means for securing the open first end of the angle attachmenthousing to the motor housing of the power tool includes at least oneslot formed in the angle attachment housing and extending from adjacentto the open first end thereof and a fastener mounted on the angleattachment housing and extending across the slot such that when thefastener is tightened the slot is pulled closed to thereby reduce thecircumference of the open first end of the angle attachment housing tosecure the open first end of the angle attachment housing to the portionof the motor housing .
 5. The angle attachment of claim 1 wherein theattachment end of the attachment shaft is adapted to have toolattachments attached thereto.
 6. The angle attachment of claim 5 whereinthe attachment end of the attachment shaft is threaded.
 7. An angleattachment for a power tool, comprising: (a) an angle attachment ahousing: ; (b) an attachment shaft mounted in the angle attachmenthousing and having a threaded attachment end extending therefrom and anattachment shaft flange mounted on the attachment end of the attachmentshaft and positioned thereon such that the threaded attachment end ofthe attachment shaft extends beyond the attachment shaft flange; (c) afirst attachment shaft bearing mounted in the angle attachment housingand positioned therein to support the attachment shaft for rotationalmovement thereof; (d) an attachment shaft a gear attached to theattachment shaft; and (e) an alignment bearing mounted in the angleattachment housing and adapted to receive a first shaft having a firstshaft gear mounted thereon to support the first shaft for rotationalmovement thereof and positioned in the angle attachment housing suchthat ; wherein when the first shaft is positioned in the alignmentbearing the attachment shaft is at an angle to the first shaft and theattachment shaft gear is engaged with the first shaft gear.
 8. An angleattachment for a power tool, comprising: (a) an angle attachmenthousing; (b) an attachment shaft mounted in the angle attachment housingand having an attachment end extending therefrom; (c) an attachmentshaft gear attached to the attachment shaft; (d) a first attachmentshaft bearing mounted in the angle attachment housing and positionedtherein on a first side of the attachment shaft gear mounted on theattachment shaft to support the attachment shaft for rotational movementthereof; (e) a second attachment shaft bearing mounted in the angleattachment housing and positioned therein on a second side of theattachment shaft gear mounted on the attachment shaft to support theattachment shaft for rotational movement thereof in the angle attachmenthousing; and (f) an alignment bearing mounted in the angle attachmenthousing and adapted to receive a first shaft having a first shaft gearmounted thereon to support the first shaft for rotational movementthereof and positioned in the angle attachment housing such that whenthe first shaft is positioned in the alignment bearing the attachmentshaft is at an angle to the first shaft and the attachment shaft gear isengaged with the first shaft gear.
 9. The angle attachment of claim 1wherein the alignment bearing is positioned in the angle attachmenthousing such that when the first shaft is positioned in the alignmentbearing the attachment shaft is at a right angle to the first shaft. 10.An angle attachment for a power tool, comprising: (a) an angleattachment a housing; (b) an attachment shaft mounted in the angleattachment housing and having an attachment end extending therefrom fromthe housing; (c) a first attachment shaft bearing mounted in the angleattachment housing and positioned therein to support the attachmentshaft for rotational movement thereof; (d) an attachment shaft gearattached to the attachment shaft; (e) an alignment bearing mountedprovided in the angle attachment housing and adapted to receive an firstshaft having a first shaft gear mounted thereon to support the firstshaft for rotational movement thereof and positioned in the angleattachment housing such that when the first shaft is positioned in thealignment bearing the attachment shaft is at an angle to the first shaftand the attachment shaft gear is engaged with the first shaft gear; and(f) a first shaft having a first shaft gear mounted thereon positionedin the alignment bearing.
 11. The angle attachment of claim 10 whereinthe first shaft includes a proximal end and a distal end, wherein thefirst shaft gear is mounted on the first shaft between the proximal anddistal ends thereof and positioned thereon such that when the distal endof the fist shaft is positioned in the alignment bearing the first shaftgear engages the attachment shaft gear, and where in the distal end ofthe first shaft is positioned in the alignment bearing.
 12. The angleattachment of claim 11 wherein the distal end of the first shaft issmaller in circumference than the proximal end thereof.
 13. The angleattachment of claim 1 comprising additionally attachment shaft lockmeans for preventing rotation of the attachment shaft.
 14. An angleattachment for a power tool having a motor housing, a motor locatedwithin the motor housing, a motor shaft driven by the motor and having amotor shaft end ex tending extending from the motor housing, and amechanical structure attached to the motor shaft end for securingattachments to the motor shaft, the angle attachment comprising: (a) anangle attachment housing having an open first end thereof attached tothe motor housing around a location where the motor shaft extends fromthe motor housing; (b) an attachment shaft mounted in the angleattachment housing and having an attachment end extending from a secondend thereof; (c) a first attachment shaft bearing mounted in the angleattachment housing and positioned therein to support the attachmentshaft for rotational movement thereof; (d) an attachment shaft gearattached to the attachment shaft; (e) an alignment bearing mounted inthe angle attachment housing; (f) a first shaft attached to the motorshaft via the mechanical structure and removably positioned in thealignment bearing at an angle to the attachment shaft to be supported bythe alignment bearing for rotational movement thereof; and (g) a firstshaft gear mounted on the first shaft and engaged with the attachmentshaft gear.
 15. The angle attachment of claim 14 wherein the alignmentbearing is mounted in the angle attachment housing in alignment with anaxis of the open first end of the angle attachment housing.
 16. Theangle attachment of claim 14 further comprising means for securing theopen first end of the angle attachment housing to the motor housing ofthe power tool.
 17. The angle attachment of claim 16 wherein the meansfor securing the open first end of the angle attachment housing to themotor housing of the power tool includes at least one slot formed in theangle attachment housing and extending from adjacent to the open firstend thereof and a fastener mounted on the angle attachment housing andextending across the slot such that when the fastener is tightened theslot is pulled closed to thereby reduce the circumference of the openfirst end of the angle attachment housing to secure the open first endof the angle attachment housing to the motor housing.
 18. The angleattachment of claim 14 wherein the attachment end of the attachmentshaft is adapted to have tool attachments attached thereto.
 19. Theangle attachment of claim 18 wherein the attachment end of theattachment shaft is threaded.
 20. The angle attachment of claim 19comprising additionally an attachment shaft flange mounted on theattachment end of the attachment shaft and positioned thereon such thata threaded portion of the attachment end of the attachment shaft extendsbeyond the attachment shaft flange.
 21. The angle attachment of claim 14wherein the first attachment shaft bearing is positioned in the angleattachment housing on a first side of the attachment shaft gear mountedon the attachment shaft and comprising additionally a second attachmentshaft bearing mounted in the angle attachment housing and positionedtherein on a second side of the attachment shaft gear mounted on theattachment shaft to support the attachment shaft for rotational movementthereof in the angle attachment housing.
 22. The angle attachment ofclaim 14 wherein the first shaft is positioned in the alignment bearingat a right angle to the attachment shaft.
 23. The angle attachment ofclaim 14 wherein the first shaft includes a proximal end and a distalend, wherein the first shaft gear is mounted on the first shaft betweenthe proximal and distal ends thereof and positioned thereon such thatwhen the distal end of the fist shaft is positioned in the alignmentbearing the first shaft gear engages the attachment shaft gear, andwherein the distal end of the first shaft is positioned in the alignmentbearing.
 24. The angle attachment of claim 23 wherein the distal end ofthe first shaft is smaller in circumference than the proximal endthereof.
 25. The angle attachment of claim 1 comprising additionallyattachment shaft lock means for preventing rotation of the attachmentshaft.
 26. A hand-held power tool adapted for use in a first arrangementas a rotary cutting tool and in a second arrangement with an angleattachment mounted thereto, the tool comprising: a housing having afirst end; a motor provided inside the housing; a motor shaft having afirst end coupled to the motor and a second end extending from the firstend of the housing; a collet nut selectively mounted to the second endof the motor shaft; a collet selectively received inside the collet nut;the tool being adapted in a first arrangement to support a rotary toolbit in the collet nut and collet when the tool is adapted for use as arotary cutting tool; the tool being adapted in a second arrangement tocouple to an angle attachment, the angle attachment comprising: an angleattachment housing, the angle attachment housing having a first endadapted for mounting to the first end of the motor housing; a firstshaft provided in the angle attachment housing and adapted to beselectively coupled to the motor shaft; and an attachment shaft providedin the angle attachment housing so that the attachment shaft is notsubstantially parallel to the motor shaft, the attachment shaft beingcoupled to the first shaft to translate rotation of the first shaft intorotation of the attachment shaft; wherein the attachment shaft has anattachment end extending from the angle attachment housing that isadapted to support a variety of attachments comprising cutting wheelsand sanding discs.
 27. A hand-held power tool according to claim 26 andfurther comprising a bearing provided in the angle attachment housing,the bearing being adapted to support the attachment shaft for rotationalmovement.
 28. A hand-held power tool according to claim 27 and furthercomprising an attachment shaft gear attached to the attachment shaft.29. A hand-held power tool according to claim 28 and further comprisinga first shaft gear provided on the first shaft, the first shaft gear andattachment shaft gear being engaged to translate rotational movement ofthe first shaft to the attachment shaft.
 30. A hand-held power toolaccording to claim 29 and further comprising an alignment bearingprovided in the angle attachment housing, the alignment bearing beingadapted to removably receive a distal end of the first shaft and tosupport the first shaft for rotational movement within the angleattachment housing.
 31. A hand-held power tool according to claim 26 andfurther comprising an alignment bearing provided in the angle attachmenthousing, the alignment bearing being adapted to removably receive adistal end of the first shaft and support the first shaft for rotationalmovement within the angle attachment housing.
 32. A hand-held power toolaccording to claim 31 and further comprising an attachment shaft gearattached to the attachment shaft.
 33. A hand-held power tool accordingto claim 32 and further comprising a first shaft gear provided on thefirst shaft, the first shaft gear and attachment shaft gear beingengaged to translate rotational movement of the first shaft to theattachment shaft.
 34. A hand-held power tool according to claim 33 andfurther comprising a bearing provided in the angle attachment housing,the bearing being adapted to support the attachment shaft for rotationalmovement.
 35. A hand-held power tool according to claim 26 , wherein thefirst end of the angle attachment housing is mounted to the first end ofthe motor housing through the cooperation of at least one slot formed inthe angle attachment housing and a fastener provided on the angleattachment housing so that when the fastener is tightened, the slot ispulled closed to secure the open first end of the angle attachmenthousing to the first end of the motor housing.
 36. A hand-held powertool according to claim 26 , wherein the attachment end of theattachment shaft is threaded.